1. The Field of the Invention
This invention relates to a shoe sole for triple-time stepping. More particularly, this invention relates to a shoe sole for triple-time stepping that has the rear portion inclined in two steps at a predetermined angle to achieve a triple-time stepping in a natural and accurate manner.
2. Related Prior Art
As shoes are considered as a means for protecting feet from external impact force, a number of functional shoes of various shapes and structures have been suggested for the purpose of providing good comfort.
In general, shoes mitigate the transmission of the impact force produced from a pedestrian's weight to the vertebra. An ideal walking gait, so called “a triple-time stepping”, is well known that a procedure of landing is followed in the order of a heel, a sole, and toes.
A conventional shoe has a heel attached to the rear portion of a shoe sole that is formed on a flat bottom surface. Such a conventional shoe has some drawbacks that a load caused by the pedestrian's weight is concentrated on the heel on walking to transmit the impact force to the vertebra, inducing pains on waist, shoulders, neck and the like, and causing deformation of toes. Also, since no triple-time stepping is achieved, the pedestrian is susceptible to fatigue while walking.
In view of the matter described above, a shoe has been proposed that the rear portion of a shoe sole has a height lower than that of the remainder portion, as shown in FIG. 1. With this construction, the shoe has a cutout 1 firstly touched on the ground on walking, thereby increasing a muscular strength and reforming a walking gait, without achieving a triple-time stepping.
To solve this problem with the above-constructed shoe, the applicant of the present invention has suggested a shoe for triple-time stepping as disclosed in Patent Application No. 239854 (under the title of “Healthful Shoe”).
The shoe of the cited patent includes, as shown in FIG. 2, a bottom portion 2 of a shoe sole in contact with the ground; front and rear recesses 3 and 4 formed on either side of the bottom portion 2; and front and rear cutouts 5 and 6 inclined upwardly from the front and rear recesses 3 and 4 to the front and rear sides of the shoe sole, respectively.
This shoe construction is designed to achieve a triple-time stepping on walking that a procedure of landing is followed in the order of the rear cutout 6, the bottom portion 2, and the front cutout 5.
However, the shoe construction concentrates a load mostly on the heel of the shoe sole on walking, so it only achieves a dual-time stepping rather than a triple-time stepping and makes the standing posture considerably uncomfortable and unstable.